Effects of pressure and temperature on the carrier transports in organic crystal: A first-principles study

By employing density-functional theory coupled with Holstein–Peierls model, we investigate the pressure and temperature dependence of the hole and electron mobilities in naphthalene single crystal from atmospheric pressure up to $2.1GPa$ (at room temperature) and from $5to296K$ (at ambient pressure). It is found that the pressure reduces the electron-phonon coupling strength and enhances the mobilities. Importantly, we point out that only when temperature-dependent structure modifications are taken into account can one better describe the temperature-dependent transport behavior. Especially, the band to hopping crossover transition temperature for the electron transport in the $c′$-axis is calculated to be around $153K$⁠, which is close to the experimental result of between 100 and $150K$⁠. If this temperature-dependent structure modifications were neglected, the transition temperature would be only about $23K$⁠, as previously obtained [L. J. Wang et al, J. Chem. Phys. 127, 044506 (2007)].